Ignition device



Nov. 6, 1956 M. F. STERNER 2,769,436

IGNITION DEVICE Filed Oct. 9, 1953 &

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- l Melvin I. Sienna! INVENTOR.

IGNITION DEVICE Melvin F. Sterner, Royal Oak, Mich., assignor to Holley Carburetor Company, Detroit, Mich, a corporation of Michigan Application October 9, 1953, Serial No. 385,177

2 Claims. (Cl. 123-117) The object of this invention is to advance the spark on an internal combustion engine:

(a) as the speed increase (15) as the load decreases and to blend these two variables so that no condition can arise, regardless of the sequence of events, in which the engine will knock due to an overadvanced spark or, on the other hand, overheat due to a late spark. Naturally, there is a band of tolerance so that the spark need not be held so closely that a commercial solution is impossible. This invention gives a practical solution to the above problems. The solution is:

This invention briefly comprises an engine operated vacuum pump which generates a vacuum which increases with speed. This vacuum is modified by a metered air leak. This air leak increases as the manifold air pressure increases.

The figure shows diagrammatically the preferred form of my invention.

10 is the air entrance, preferably including an air cleaner, to the carburetor 12 controlled by the throttle 14.

16 is the inlet manifold.

18 is the passage from the inlet manifold 16 to a chamber 20.

Inside the chamber 20 is mounted an exhausted, or partly exhausted, bellows 22.

24 is a needle valve controlling a restriction 26.

Atmospheric pressure is derived from air cleaner through pipe 11.

28 is a T-shaped pipe with three armsfirst, one to the restriction 26; and second, one to the diaphragm chamber 30; third, one to the entrance to vacuum pump 32 through an inlet valve 34 past a restriction 36.

31 is the diaphragm to air chamber 39.

The pressure in this diaphragm chamber is determined by the speed of operation of pump 32. 7

Pump 32 is driven by the shaft 38 which also drives the circuit breaker cam 40 and the high tension element 44 shown in broken lines.

46 is a rod operatively connected to the diaphragm 31 which rotates the circuit breaker plate 48, a circuit breaker pivot 49 carrying circuit breaker arm 47 around the outside of bushing 50.

The inside of bushing 50 serves as a bearing for the shaft 38. The circuit breaker arm 47 is operated by the cam 40 in a well-known manner.

The pump 32 is the subject of our co-pending application Serial No. 352,413 filed May 1, 1953, by Eugene C. Bettoni and Kalin S. Johnson.

Briefly, a pair of rollers 5254 mounted on a crossshaft 56 driven by a drive shaft 38 ride on a cam surface 58 (shown in broken lines). This cam rides on an annular plate 60 which is suppored by the spring 64 under the flexible diaphragm 62. 7

States Patent Hence, as the shaft 38 rotates, then the diaphragm 62 reciprocates. A tongue and groove joint 66 connects driven shaft 68 with driving shaft 38. Driven shaft 68 carries the driving means for high tension distributor 44 (shown in broken lines) driven by the flat spring 42 mounted on the end of shaft 68.

70 is the outlet passage leading from pump.

74 is a valve.

72 is a spring seating the valve 74.

34 is a similar spring loaded inlet valve.

The valve 24 closes the orifice 26 as it is moved to the left under the influence of a fall in pressure in the manifold 16. Hence, when the throttle 14 is opened the reverse movement takes place and the orifice 26 is opened as the needle is moved to the right when it is returned to its original position. The spark is thus retarded at low speeds with the throttle 14 wide open. At high speeds however, it is advanced as there is then an increase in flow through orifice 26. If the valve parts 20, 22 and 24 are omitted, the spark advance responds only to speed. In certain industrial installations this is a satisfactory control and parts 20, 22 and 24 are not needed and should be omitted.

This increase in flow lowers the pressure in pipe 28 and in the diaphragm chamber 30.

To advance the spark for road loads when the throttle 14 is closed, the following events happen: the pressure in inlet manifold 16 falls; the pressure in chamber 20 falls; the valve 24 closes the opening 26; the pressure in chamber 34 falls; the diaphragm 31 and rod 46 move to the right; the circuit breaker 47 and its plate 48 then rotate clockwise when viewed from above to advance the spark. The area of the two restrictions 36 and 26 and the shape of the needle valve 24 determine the characteristic of the spark control. As the density of the air increases due to a rise in the barometer and/ or to a fall in temperature, and vice versa, the vacuum is modified to retard or advance the spark in accordance with engine requirements.

What I claim is:

1. In an ignition system for an internal combustion engine, a drive shaft driven by said engine, vacuum air pump operated thereby having an air entrance and a restriction in said air entrance through which atmospheric air is admitted to said pump, a circuit breaker, a plate supporting saidcircuit breaker, a cam driven by said engine and engaging said circuit breaker, a daiphragm, a link from said diaphragm to said plate, a spring rotating the plate, a diaphragm chamber enclosing said diaphragm, a passage from said chamber to the suction side of said pump connected to the downstream of said restriction so that the pressure in said diaphragm chamber falls as the speed of the engine increases and the spark is advanced.

2. A device as set forth in claim 1 in which there is an inlet manifold and a throttle valve and in which there is a valve located in said air entrance to close the admission of air to said air pump, means responsive to inlet manifold suction to close said valve at low inlet manifold pressure'so that the pressure in said diaphragm chamber falls whenever the engine throttle is closed.

References Cited in the file of this patent UNITED STATES PATENTS 2,270,982 Vanderpoel et al Ian. 27, 1942 2,317,885 Colvin Apr. 27, 1943 2,359,231 Mallory Sept. 26, 1944 2,409,053 Mallory Oct. 8, 1946 

